x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper function

The PUSH_AND_CLEAR_REGS macro is able to insert the GP registers
"above" the original return address. This allows us to move a sizeable
part of the interrupt entry macro to an interrupt entry helper function:

   text	   data	    bss	    dec	    hex	filename
  21088	      0	      0	  21088	   5260	entry_64.o-orig
  18006	      0	      0	  18006	   4656	entry_64.o

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Dominik Brodowski <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Denys Vlasenko <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7a53879ec6892fda53ce0a54a67fd9c108dd3215..b0ae0c3e3815b64d77abbae729c3c6f7c5a09961 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -525,6 +525,14 @@ END(irq_entries_start)
  *
  * Entry runs with interrupts off.
  */
+ENTRY(interrupt_entry)
+       UNWIND_HINT_FUNC
+
+       PUSH_AND_CLEAR_REGS save_ret=1
+       ENCODE_FRAME_POINTER 8
+
+       ret
+END(interrupt_entry)
 
 /* 0(%rsp): ~(interrupt number) */
        .macro interrupt func
@@ -536,8 +544,7 @@ END(irq_entries_start)
        call    switch_to_thread_stack
 1:
 
-       PUSH_AND_CLEAR_REGS
-       ENCODE_FRAME_POINTER
+       call    interrupt_entry
 
        testb   $3, CS(%rsp)
        jz      1f